Problem: Add. $31.88 + 57=$
There are many ways to solve this problem. Let's see two ways we can solve it. Place value table Let's line up the numbers by their decimal places. Tens Ones $.$ Tenths Hundredths $3$ ${1}$ $.$ ${8}$ ${8}$ $5$ $7$ $.$ ${0}$ ${0}$ Because ${57}$ is a whole number, we can add a decimal point and two $0$ 's behind to make the columns align. Now, let's add each place value column. Tens Ones $.$ Tenths Hundredths ${3}$ ${1}$ $.$ ${8}$ $8$ $+$ $5$ ${7}$ $.$ ${0}$ $0$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $8$ $8$ $.$ $8$ $8$ Decomposing the numbers We can group the whole numbers together and the decimals together. $\begin{aligned} &({31} + {57}) + {0.88}\\\\ &=88 + {0.88}\\\\ &=88.88 \end{aligned}$ $31.88 + 57=88.88$